The present invention relates to a new and improved construction of rolling apparatus or rolling mill.
In its more particular aspects, the present invention relates to a new and improved rolling apparatus comprising a controlled deflection roll which contains a non-rotatable or stationary support or beam and a roll shell which is rotatable about this stationary support or beam and which is supported along its length at such stationary support or beam. The rolling apparatus further comprises a counter roll containing supporting means which are arranged in such a manner as to face supporting means for supporting the roll shell at the stationary support or beam of the controlled deflection roll.
Such rolling apparatus as known, for example, from U.S. Pat. No. 3,119,324, granted Jan. 28, 1964, or Swiss Pat. No. 623,369, granted May 29, 1981, serve, for instance, for dewatering, calendering or other treatment of web-shaped materials like plastics, paper, cardboard or textile material and can also be utilized for rolling metal foils or bands. Controlled deflection rolls, by means of which the pressing force effective between two rolls can be adjusted or balanced over the width of the rolls, have been found particularly suited for such purposes in order to achieve, across the width of the treated web of material, a treatment which is especially uniform, which can be adapted to the requirements or which can compensate for defective roll profiles. It is a prerequisite for achieving this objective that the roll nip or gap existing between the controlled deflection roll and the counter roll corresponds, across the entire width, as precisely as possible to the desired profile and in particular cases, for example, can be maintained constant. Since, however, the pressing rolls are of different constructions in most cases, the bending lines of the two rolls do not have the same shape and there results, as a consequence, a non-uniform roll nip or gap. While a large portion of such non-uniformity can be compensated for by using different pressing forces in different zones of the controlled deflection roll, nevertheless such significantly restricts the useful efficiency of the zone control.
As already described in the previously mentioned Swiss Pat. No. 623,369, the aforementioned deviations can be greatly reduced and the bending lines of the controlled deflection roll and of the counter roll can be better matched or accommodated to one another when the supporting means for the roll shell at the support or beam of the controlled deflection roll and the supporting means for the journals of the counter roll are arranged in the roll stand of the rolling apparatus in such a manner as to face each other and to be equidistant. In such arrangement the journals of the counter roll which may be designed as a solid roll or as a tubular roll, are fixedly connected with the roll body and rotate conjointly therewith. The practical utilization of this concept, however, is very limited since the spatial conditions, particularly for the arrangement of the various supporting means, require a special roll stand and additionally prevent or exclude the improvement of existing rolling mill or apparatus by reconstruction or retrofitting.
While the aforementioned problems may be solved by using two similar controlled deflection rolls which counteract each other, such solution, however, would require in practice that the constructional expense and the costs are doubled, apart from the necessity of using complicated control means.